In the conventional color printer which reproduces input image data with a smaller number of colors than those specified by the data in one dot, an image processing for reproducing an image with the same number of colors as those specified by the input data is executed. For instance, each output color such as Y (Yellow), M (Magenta), C (Cyan), or R (Red), G (Green), and B (Blue) is adjusted to a number of gradations which can be reproduced in one dot by using the intermediate gradation reproducing method known as the dither method or error diffusion processing to express the image with multiple gradations, thus a number of reproduced colors being increased.
For instance, as a typical one, there is an image processing apparatus, as shown in FIG. 11, comprising a color correcting section 1101, a dither or error diffusing section 1102, and a printer 104. With this configuration, color data Lab inputted to the color correcting section 1101 is subjected to the dither processing or the error diffusion processing and is then subjected to a color correction processing to convert the input color data to signals for controlling an output from the apparatus, namely 8-bit data for Y, M, C, and K, respectively.
Then in the dither or error diffusing section 1102, the signals are corrected to 1 to 7-bit data for output for each of Y', M', C', and K', and the data is sent to the printer 104, thus a multi-gradation image being outputted.
However in the image processing apparatus as described above, as a simulated intermediate gradation image is reproduced with dot configuration by subjecting Y, M, C and K signals to the intermediate gradation reproducing processing such as the dither processing or the error diffusion processing, sometimes an unpreferable image called texture a image may be generated, and also as either one of the two types of processing described above is executed independently, it has been difficult to reproduce accurately the same colors as those specified by the data.